The present invention relates to a nail gun switch mechanism, and particularly to a nail gun switch mechanism for switching the nail gun operation in a sequential actuation mode and a contact actuation mode.
In pneumatic nail guns, a hitting bar is driven by compressed air momentarily to push a nail into a workpiece. The hitting bar is controlled cooperatively by a trigger and a safety slidable bar on the nail gun body or a hitting base connected with the safety slidable bar.
Actuating nails for a pneumatic nail gun generally can be divided into two kinds, one is the sequential actuation mode (or the restrictive mode) and the other is the contact actuation mode.
The sequential actuation mode means the operator firstly should set a safety slidable bar or a hitting base on the safety slidable bar contacting on a workpiece to push an upward movement of a trigger lever, and then press a trigger to bring the trigger lever to actuate a trigger valve. In this mode, if the operator wants to actuate again, he should release the trigger first, and then repeat the above actuation processes. If the operator disobeys the operating sequence, i.e. first pressing the trigger and then pressing the safety slidable bar or the hitting base of the safety slidable bar, the trigger lever in the trigger can not be brought to actuate the trigger valve and nails in the nail gun is held to be driven. Thus, no dangerous accidental shot happens when the safety slidable bar or the hitting base of the safety slidable bar is wrongly touched by somebody.
The contact actuation mode means the operator should first continuously press the trigger, and then move the safety slidable bar or the hitting base of the safety slidable bar on the workpiece to perform continuously contact hitting, which makes the trigger lever brought to upwardly move and actuates the trigger valve to continuous shot. In addition, the contact actuation mode also allows the operator first sets the safety slidable bar or the hitting base of the safety slidable bar on the workpiece to bring the trigger lever to upwardly move, and then individually or continuously presses the trigger to respectively actuate single or multiple nails for fastening the workpiece.
These two actuation modes are both used in a nail gun by utilizing a switch mechanism to realize switching of the sequential actuation mode and the contact actuation mode. As shown in U.S. Pub. No. 20050184120, a rotating rod is included in a contact safety assembly, which is constructed to slide toward/away from a driver housing. The rotating rod includes a first shoulder or ledge and a second shoulder, which is off-set from the first shoulder. The rod may be rotated (not swung) to orientate a selected shoulder to touch a trigger lever in the trigger so as to permit selection between a contact actuation mode and a sequential actuation mode. However by having the two shoulders respectively touch the trigger lever during actuation mode switching, the rotating rod generally has a complicated structure, which needs to be improved.